body{
    margin:0;
    padding:0;
    background-image:url("../img/bg1.jpg");
    background-size:cover; /* 把背景图像扩展至足够大，以使背景图像完全覆盖背景区域。 */
    font-family:"YouYuan";

}

.login{
    box-sizing:border-box;
    box-shadow:0 10px 20px rgba(0,0,0,0.4);
    margin:0 auto;
    margin-top:150px;
    width:500px;
    padding:30px;
    background:rgba(0,0,0,0.3);
    border-radius:20px;
}
.container .login:hover{
    background-color:rgba(0,0,0,0.2);
}
.login h2{
    margin:0 0 20px;
    text-align:center;
    color:white;

}
.login .input-box{
    position:relative;
}
.login .input-box input{
    width:100%;
    padding:10px 0;
    font-size:16px;
    color:white;
    margin-bottom:25px;
    border:none;
    outline:none;
    background:transparent;
    border-bottom:1px solid white;
}
.login .input-box span{
    position:absolute;
    top:0;
    left:0;
    padding:10px 0;
    font-size:16px;
    color:white;
    pointer-events:none;/*值none表示鼠标事件“穿透”该元素并且指定该元素“下面”的任何东西*/
    transition:.6s;
}

.login .input-box input:focus ~ span
,.login .input-box input:valid ~ span{
    top:-20px;/*文字向上移动*/
    left:0;
    color:#adadad;
    font-size:15px;
}
.login input[type="submit"]{
    background:transparent;
    border:none;
    outline:none;
    color:white;
    background:#6d6d6d;
    padding:10px 20px;
    cursor:pointer;
    border-radius:5px;
    box-shadow:0 5px 10px rgba(0, 0, 0, 0.3);
    width:130px;
    font-size:18px;
}
.login-button
{
    display:flex;
    justify-content:space-around;
    align-items:center;
}
.login-button .login-btn:hover{
    background-color:#555454;
}
.login-button .register{
    color:#cecaca;
    text-decoration: none;
}
.login-button .register:hover{
    color:white;
    cursor:pointer;
}

/* 底部版权信息样式 */
.footer .copy-box{
    margin-top:120px;
    color:white;
    text-align:center;
    font-size:16px;
}
